Apparatus for electro treating



Oct. 4, 1966` L. E. LANcY APPARATUS FOR ELECTRO TREATING Filed July 51, 1962` Murau INVENTOR.

vL ESL /E E. LANCY HLS` A TTORNEYS United States Patent O 3,276,985 APPARATUS FOR ELECTRO TREATING Leslie E. Lancy, Ellwood City, Pa., assignor to Lancy Laboratories, Inc., Zelienople, Pa., a corporation of Pennsylvania Filed July 31, 1962, Ser. No. 213,826 Claims. (Cl. 204-203) This invention relates to procedure and apparatus for electro treating and more particularly, to material-handling apparatus and procedure for electro treating or plating continuous, flexible, Work pieces or materials, such as metal chain, thin metal strip, wire or stretchable material.

In accordance with the prior art of which I am aware, electroplating of individual Work pieces is accomplished by employing a plurality of hooks which engage and carry at least one work piece through the electrolytic bath, see my Patent No. 2,887,447. Where, however, it is necessary to electroplate a long c-ontinuous piece of material, such as a continuous metal strip, apparatus of the type described in my Patent No. 2,933,438 may be employed. In electroplating strip, the Work piece is pulled over contact and guide rolls, and through the bath under tension as exerted by a positively-acting pinch roll pass. This keeps the strip tight and prevents it from dragging on the bottom of the tank and rising above the surface of the fluid. However, I have found that with chain or other flexible or stretchable material, pulling tension presents difficulties. If a chain is electroplated under this type of tension, the links Will tend to remainin a static relationship with each other through the electro treating bath, will tend to become electroplated together, and the region where the adjacent lengths touch will not be electroplated.

In endeavoring to find a solution to the problem of moving a flexible or stretchable work piece or material continuously along an electro treating line in such a manner as to avoid damage to the material and, at the same time, to accomplish a good and substantially uniform electroplating action during such movement, I have found that there are a number of yinter-dependent somewhat complex factors involved. In the first place, as above indicated, I Vfound that it was highly important to avoid tensioning or stretching the material during its movement, if a good retained electroplated surface is to be provided, and that contrary to the usual practice in electroplating a continuous non-stretchable material, tension on the material during its movement was highly disadvantageous. The question then Iarose as to Whether the work material could be properly moved and electroplated without tension movement and if so, how movement could be effected in such a manner as Vto provide a sound electro- -plated surface.

In reaching a solution to Vthe problem, I found that it was necessary t-o provide means to continuously and somewhat irnpositively move or advance the flexible or stretchable work material with a somewhat loose, flexible, tension-free, line type of movement, and that this could be accomplished if suitable driving means in the nature -of a traction means-could be devised for use at the entry and exit ends of the line. I also found that what may be termed guiding and positioning means is needed to support the work material and move along the line with it to retain itslength in a substantially tension-free-and loose, flexible relationship. Feed and delivery means at oppo- 3,276,985 Patented Oct. 4, 1966 l CC site ends of the line is needed to progressively feed the Work material, without a fully positive connection or fully positive friction or traction engagement therewith, in order to avoid tension pull and permit a flexible loose, dangling or swingable, conforming movement of its portions along the line, as supported on the guide and positioning means. As to the means employed for effecting movement of the work material or length, I determined that such means should be operated or driven in such a manner, and, in combination with the guide and positioning means, as to enable a loose, dangling or flexible relationship of the length of work material while, at the same time, assuring a trouble-free and a substantially planar movement through active electro-treating por-tions or stations of the treatment line.

As .to a magnetic Work piece or material, such as of iron or steel, such drive means may be in the nature of magnetic rolls that magnetically hold the work material in place and progressively advance it during their rotation. In the case'of a non-magnetic work material or piece, friction-slip roll passesV or a roll and resilient hold-down block may be employed; the rolls may have rubber or resin faces. As to a roll pass, the upper roll thereof may have a resilient, eXcess-force-sensitive upward release, such as a relatively light tension spring mounting for this purpose.

For guiding the work piece through the line, I have `determined that .a plurality of longitudinally, substantially uniformly, spaced-apart transverse hanger, support or carrier arms could be employed on which the work material would rest, ,but with respect to which it will be free to'flex land dangle and which Will permit Vintermediate portions between a spaced pair of such hanger means to conform during its movement to a desired path of travel, without positive restraint, between its points of support. VIn this connection, I found'that it was advisable to positively move the hangers along the line as a part of a continuous conveyor system and, atsubstantially the desired rate of movement of the strip material, and to mini` 'mize friction-slippage between `the work material and the Ihangers during vsuch movement.

It ihas thus been 'an object of fmy invention to devise a solution tothe .problem of providing a practical, effective `and efllcient method of electro vtreating flexible or stretchable, continuous-length, work material or pieces.

Another object has been -to provide improved appara- Y tus and procedure for `electro treating or electroplating work material of infinite length. y

Another object 'of my invention is to provide an improved Vmethod of an apparatus for kcarrying Work material to be electro treated 'through processing stations or 'tanks of Va treatment line.

`A furlther object of my invention is to devise apparatus particularlyl suitable for transporting flexible or stretch- Aable :material longitudinally 'through an electroplating process. Itis `au ancillary object `of my invention to provide yan approved support 'arm construction for use in an electroplating bath and for supplying electricity to the `material :being treated.

In practicing my invention, I utilize a longitudinal line of .treating tanks -or stations along with the work material, piece or pieces are to =be moved. A continuous :(return) chain conveyor is operatively positioned to, in'ts lower span, positively move -a longitudinally-spaced, continuous vseries of guide support hangers, carriers or 3 larms along working levels of the treatment line and to return such hangers alongan upper non-working level of the line in continuous movement. The hangers, carriers or arms are adapted to, vat the entry end of the line, move under progressive length portions of the continuous length of work material and loosely carry and support such portions ot the material during their movement between various stations of the line and until the material reaches the end of the line and is ready for delivery in a linished electroplated condition. During this time, the work material is being somewhat impositively moved in a loose relationship 4between powered rollers at the entry and exit ends of the treatment line. At the exit end .of the line, the hangers move upwardly out of their supporting relationship with Ithe wor-k materials and are then carried back overhead to a return position at the entry end of the line.

As shown in the illustrated embodiment, the hangers may be pivotally suspended to permit swinging action during certain phases of the treatment, such as Ialong rinsing, acid dip, drag-out, waste collection, dichromate and drying processing of the material. However, at other portions of the treatment line, such as during electroplating and electrocleaning, means is provided for `retaining the hangers, carriers or arms in a nonswin-gable, substantially fully vertical relationship to thus retain the work material in a substantially horizontally or longitudinally straight or planar relationship during such phases of its treatment movement. The hangers, carriers or support arms for the w-ork material have transverse portions on which the material yrests and which supply the material with energizing electricity of one potential. Such portions as are moved in a submerged relationship through the treating liquids or baths are especially designed to Iresist electro-action and, `at the same time, to eiciently supply electric current to the supported portions of the work material. The immediate means upon which the work material, strip or length rests and makes electrical contact is of a material which is relatively resistant to electroplating action and is so constructed and positioned that it can be easily removed for cleaning and .replacement as the occasion may arise. More specifically, in accordance with the illustrated embodiment of my invention, I provide a group 'or a plurality of processing tanks or stations -for accomplishing `a series of steps in an electro .treating or electroplating operation or line. At the entrance end 'of the series, I provide a powered roll for gently feeding, in a positive direction, the material to Ibe treated, into the line. At .the output end of the series, I provide a powered roll for gently and positively raising the material to be treated out of the tank, with sutlcient traction for such raising action, but within insuicient traction to drag the material across supporting hangers Within the tank. A plurality of horizontal hanger arms or support hangers are carried by a trolley that above-rides on a continuous track to carry the material to be treated gently along or through the treating line.

These hanger 4arms are constructed to be open towards one transverse side 'of the line, so that when they reach the end of the series of tanks, the continuous work material or piece being treated, such as chain, may be lgently Araised .up ol of .them and moved olf to one side, while they are rotated in -an opposite side direction for the return trip. The support arms in the preferred embodiment of my invention, employ a conductor bar of a conducting metal, such as copper, for current ow and a support bar of a lstrong material such as steel, to provide rigidity; they are attached together as a stacked pair, and coated as a pair with a non-conductive mate` rial or -resin on sides and bottom thereof. A top bar of a suitable conductive but electro-inactive metal, such -as cast iron, lies over or is placed on the set or pair and is detachably-mounted by a gravitational attachment, such as pins, lon which it rests. The top Ibar has a relatively low electrolytic attraction and is substantially` co-extensive with portions of the pair of bars that are` adapted to extend into the chemical treating baths to protect them from electrolytic action. A plurality of non-conducting or resin projections are mountedon or inserted in .the upper side of the .top bar in a spaced relationship along the length thereof for separating a plurality of lengths of chain or other work material which may be `treated at the Isame time.

The novel features that I consider characteristic of my invention are set forth in the appended claims.` The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understoodfrom the kfollowing description and illustrated embodiment when read in connection with the accompanying drawings in wh-ich:

FIGURE l is a schematic plan viewof electro treating apparatus employed in accordance with my invention showing the general 4organization but with stabilizing means omitted and showing a few of the hangers.

FIGURE V2 is a schematic elevational view of the apparatus shown in FIGURE 1.

FIGURE 3 is fan enlarged fragmental side view, partially in section, showing details of carrier means and of the mounting and construction of hangers employed in accordance with the preferred embodiment of my invention.

FIGURE 4 Iis an `end view, partially in, section, on .the scale of FIGURE 3 and taken in the direction of travel of a hanger and support therefor, along the line 4-4 of FIGURE 3.

FIGURE 5 is a greatly enlarged cross-section ofza han-ger arm, taken along the line 5-5 of FIGURE4.

FIGURES 6 and 7 are cross-sections on the scale `of FIGURE 5, taken respectively along the lines 6--6 and 7--7 of FIGURE 4.

FIGURE 8 is a schematic plan view of feeding apparatus in accordance with an `embodiment of my` invention.

And, FIGURE 9 `is a schematic elevation of the apparatus shown in FIGURE 8.

I have illustrated apparatus for a exible or stretchable material or work piece of l-ong length, such that it may be considered endless or continuous, as moved along a path through an electro treating apparatusor line,'including a plurality of stations or baths. The apparatus employs a continuous, upper, guide track 10 having suspended therefrom a plurality of hangersor support arm structures for supporting lengthwise-extending material or a work piece or pieces 9 (indicated by the dotted line of FIGURE 2). The track 10 has a second component, namely a lower stabilizing track 12 (see also FIGURES `1 and 2 of my Patent No. 2,887,447), along electro-treating stationsv or baths A and E of the line. The track 12 extends along baths or l stations A and E of FIGURE -2 to stabilize movement of the hanger arms during electro treatment of the work material. iThe track 10V changes in elevation as it passes through dilerent parts of the processing line,'but the upper supporting track 10 and the lower stabilizing track i 12 are of the samedistance apart throughout. The upper supporting track y10 is shown in the form of an I-beam or an H-beam lying on its side, in order that a pair of rollers 32 may ride on its lower edges or anges (see also FIG- URE 4). The lower stabilizing track 12 has two transversely spaced-apart sections, shown in the form of two separated L-shaped pieces that are reversed with respect to each other, in order that bottom rollers 34 and 36 may y engage them for stabilizing the hangers.

Each hanger comprises a strong, intermediate, transverse support member or bar 14 (preferably of steel) of substantially rectangular cross-section; it normally rides horizontally and has, at one end thereof, an .extension `in r a vertical direction leading up, but spaced from connection with an upper angular arm or support strap member 16..`

The-arm 16 is fastened to a lower, transverse, conductor member or bar 18, but is shown electrically insulated therefrom. In FIGURE 4, bolt and nut assemblies 19 have insulating sleeves and a spacer strip of a suitable material, such as a resin, that insulate the arm 16 from .negative electrical currentV being supplied to the bar 18.

A Contiguous with and substantially co-extensive with the lower horizontal portion of the intermediate or support bar 14, is the transverse conductor member or bar 18 (preferably of copper) that is removably secured thereto in an abutting relation along its horizontal extent. The bar 14 adds rigidity and support to the conductor bar 1'8. The conductor bar 1.8 extends up to and overlaps the arm 1-6 to provide a path of good electric-a1 conductivity. An electrical strip or conductor cable 17 is shown connected to the conductor bar 18 near the upper end portion thereof and across to a sliding contact shoe or contact 20. The

`contactor 20 makes continuous sliding contact during certain portions of the cycle with electrical bus bars 21 (preferably of copper or brass) in bath A and bath E.

The conductor member 18, the support member 14 and a top closure bar or member 24 constitute a supporting arm for the hanger. The pair of members 14 and 1'8 are coated on their sides and on the bottom of the pair with a non-conducting cover material 22 (preferably a resin),

`in order to protect them from the electro treating or electroplat-ing iluid; in their Vertical section, where they extend toward the arm 16, they are fully enclosed or coated allaround with the resin to protect them from electrolytic action.

The upper side ofthe intertting pair or combination of members 14 and 18, in the region where they are horizontal, is left exposed. On top of this exposed surface, I

place the top or closure bar 24 (preferably of cast iron) which is contiguous with the pair of members and substantially vertically co-extensive therewith to cover the exposed or uncoated portions of the pair. The sup-port bar 14 and the conductor bar `18, along their lower horizontal section, are removably fastened together by ushhead cap screws 26 (preferably of steel) that extend upwardly from within the cover 22, from the bottom side of the bar 18 into the bar 14 to hold the two bars 14 and 118 tightly together and improve electrical conductivity and supporting action therebetween.

Periodically, along the horizontal section of the supporting arm, lI provide a plurality of dowel pins 28 (preferably of steel) that extend down into the support bar 1-4 and up 'into but notthrough the upper bar 24. These pins 28 'serve to removably hold or to gravitationally-mount the cast iron bar 24 in place and prevent horizontal movement Vof the upperbar 24 with respect to the intermediate bar `14. The pins 28 enable the bar 24 to be readily lifted o for cleaning and replacement. It will be noted that cast ir'on is resistant to electroplating action.

i At periodic intervals along the length of the top bar 24, I pr-ovide non-conductor (resin) removably secured spacer means 30, shown in the form of bolt and washer assemblies; the washers and the bolt heads extend a substantial distance above the upper surface of the bar 24 and their threaded ends extend into the upper bar 24. The spacer means 30 are employed so that their heads or projecting portions maybe employed to position transversely-spaced longitudinal lines of work material.

Although, for simplicity of illustration, I have shown only a few representative hanger arms 16, it will be understood that they will be carried along the full length of the conveyor in -a manner such as illustrated in my Patent No. 2,887,447. A trolley supporting mechanism for each of the hangers comprises a pair of upper, vertical supporting rollers 32 that rotate around a horizontal axis and that are held in position or guided within an upper, U-shaped, vertical arm 33 to ride on the lower tiange of the beam 10 which constitutes the supporting track. The arm 33 has a link mounting 33a that carries ya hinge pin 33b to swingably suspend a lower vertical arm assembly 35 therefrom.

The anm assembly 35 carries two pairs or sets of rollers for stabilizing it during its movement. A first or horizontal set of stabilizing rollers 34 have Vertical axes, are in spaced relationship, and substantially ll the gap between a' pair of the longitudinally-extending, angle-'shaped stabilizingv or guide track sections 12. The rst pair of stabilizing rollers 34 prevents the arm assembly 35 from swinging transversely and aid in guiding it during its longitudinal movement along the treatment line.

At a lower level and, off to the side rom the position of the first set of stabilizing rollers 34, is a second or vertical pair of stabilizing rollers 36. The second pair of rollers 36 have horizontal axes and are located to ride tightly against the lower surfaces of the stabilizing track sections or members 12. -T he second pair of stabilizing rollers 36 prevent the hanger member assembly 35 from rotating about an axis parallel to the direction of longitudinal movement and also aid inguiding it duri-ng its movement.

I-t w-ill be noted from FIGURES 3 and 4 that the rollers 34 ride between opposed vertical ilanges of the track sections 12, and that the rollers l36 Iride on under or bot-tom horizontal anges thereof. The assemblies of upper and lower arms 33 and 35 are `suspended in a' longitudinally spaced relation with each other by a continuous conveyor chain 37 for exible movement along the plating line. As shown in FIGURE 1, the hangers or work piece carriers are moved in a continuous path, such that one group is Iready to support a length of work material while another group is returning to a processing line startling position.

At the input end of the series of stations or tanks, I provide a magnetic roll 38 for work material that is 4subject to magnetism, such as steel; the roll is employed to pull the work material out of a container or reel in or on which it arrives and to gently lay the work material on successive hangers as they pass by.

At the output end of the treating line or series of tanks, I provide an output magnetic -roll 40 for picking the work material up olf the hangers and for guiding it into a delivery container or to a delivery reel. This roller is located above the level of the hangers, so that the work material is lifted up -oi of each hanger to allow the hangers to freely .turn ou its track for a return trip. The magnetic roll 40 supplies just enough tension to pick the work material off the hangers, but not enough tension to drag the work material across the hangers.

While I prefer to use magnetic rolls, itis understood that, Vin certain circumstances, such as with .non-magnetic material (copper, etc.), it may be desirable to'use a fric- -tion roll pass at each end of the line. Each roll may be covered with a rubber-like (insulating) material. The pair of rolls for each pass, like the individual magnetic rolls 38 and 40, will be coordinated in their rotation to interact and maintain :the work material -being treated in a loose relationship, as it is moved on the carrier or hanger arms along the treatment line. Also, I may use a hold-down block a-t each end of the line that cooperates with an associated driven roll and that releases by moving upwardly when the motor drive for its associated roll is stopped or de-activated.

I have shown a stainless steel stripper plate 39 at the roll 40 to facili-tate removal of the work piece. I have thus provided apparatus for electro treating or electroplating exible or stretchable material whereby the material being treated is not drawn tautly through the process but instead is carried loosely through on a group of transverse, longitudinally spaced-apart hanger carriers. The work material is therefore allowed to swing freely wtkroughout its processing and is handled gently, so that it is not unreasonably deformed during 'its processing; it is swingably guided 4through suitable treatment line areas or stations and is positively guided through other areas or stations. Y

As' shown in FIGURE l, the magnetic rolls 38 and 40 krollers 34 and 36 are in a guided engagement with the lower track sections 12. By way of illustration, A is an electro cleaning, B is a rinse, C is an acid dip, D is a rinse, E is an electroplating, F is a dragout, G is a waste treatment, H is a rinse, I is a dichromate treatment, I is a waste treatment, K is a rinse, L is a hot rinse, and Mk is a dryer station or zone.

In accordance with my invention, one or a group of transversely adjacent lengths of work material may be moved along the treatment line. Where a group is to be simultaneously progressively electro treated, individual work piece lengths can be supplied to and taken off the line, if desired, at spaced positions adjacent its end and at oblique angles with respect thereto for facilitating individual handling of each work material length. I have illustrated such an arrangement as applied to the entry end of the treatment line in FIGURES 8 and 9,.

What I claim is:

1. In a system for electro treating a work material of indefinite length and in the nature of a flexible or stretchable material, a series of treatment stations defining a treatment line for treating the material, a driven roll at an entry end of said treatment line and a driven roll at a delivery end thereof engaging successive portions of the work material to advance it along said treatment line, said driven rolls having means effecting an impositive engagement with the work material and the speed of said rolls being coordinated to advance the work material along said line n a substantially tension-free condition, a conveyor operatively positioned along said line, a plu- -rality of open-end hangers carried in a longitudinallyspaced relation on said conveyor .to pick-up successive portions of the work material 4at the entry end of said line and guidably-support and move with such successive portions during the advance of the work material along said line, and means progressively disengaging said hangers through their open ends from the successive portions of the work material adjacent the delivery end of said line and being again returned by said conveyor to the entry end of said line.

2. A work piece support hanger for use in an electro treating system having a trolley, a suspension arm connected to said trolley and extending downwardly in an angular relation thereto, a horizontal work lpiece support arm structure connected to said suspension arm; said' support arm structure having a strong metal supportbar and a conductor bar in an abutting relation with each other, said conductor bar and said support bar being removably secured together as a pair, said pair being coated on its sides and bottom with a non-conducting material, a top closure bar along the exposed top of said pair, and a gravitational connection for posi-tioning said top bar with respect to said pair. p

3. An electro treating system -for treating a continuous length of a flexible ,or stretchable work material which comprises, a treating line made up of a group of longitudinally-aligned treating stations, means engaging and driving successive portions of the work material length at entry and delivery ends of the line to Vthereby progressively advance the work material length therealong, means progressively subjecting the work material length to electro treatment along the line, said rst-mentioned means coordinating the speed of the driving-engagement at the entry and delivery ends of the line .to maintain the work material length in a tension-free condition along the treating line, means guidably-supporting the work material` length along the line between the entry and delivery ends thereof; said means lfor guidably-supporting the work material length comprising, a trolley positioned` along said line, suspension arms connected to said trolley in a longitudinally spaced rela-tion with respect to each other and extending downwardly in an angulary relation with respec-tto said trolley, horizontal work piece support arms connected to said suspension arms, each of said support arms having a metal support bar `and a conductor bar in an abutting and removablysecured together rela tion with each other as a pair, non-conducting material along side and bottom portions of said pair, a top closure bar positioned along the exposed top of said pair having means for receiving the continuous length of work mate`` rialV thereon,f a gravitational connection for positioning said top. bar onsaid pair, and means for supplying electrical current through said pair and said top 4bar to the work material length.

4. In a system as defined in claim 1 wherein said means effecting an impositivo engagement is of resilientcon-.p

struction.

5. In a system as defined in claim 1 wherein said means` effecting an .impositive engagement is magnetic means` carried by said rolls.

6. An electro treating system for treating a continuous therealong, means for progressively subjecting .thel work material length to electro treatment along the line, said first-mentioned means including means for yguidablysupporting the work material along Ithe line between the entry and delivery ends thereof, and said -rst-mentioned means having impositivo-driving work material engaging means cooperating with said guidable-supporting means to coordinate the movement of the work material between the entry and delivery ends of the line lto maintain `a tension-free movement of the work material along the treatment line.

7. A system as defined in claim 6 wherein, the work material is of a magnetic metal, and said `impositivedriving means has magnetized means to magnetically maintain an impositive driving engagement with successive portions of the work material length as it is progressively advanced along the line.

8. A system as defined in claim 6 wherein said means for guidably-supporting a work material length comprises longitudinally spaced-apart hangers along said line, and said coordinating means includes means for moving said hangers along said line independently of first-mentioned means and into an under-supporting position with the work material length at the entry end of and out of such a supporting position at the delivery end of said line..

9. A system as dened in claim 6 wherein, continuous conveying means carries said means for guidably-supporting the work material length in a forward substantially horizontal planar path along the treating line and in a backward substantially horizontal planar` path `above the line of the forward movement, and means is associated with said conveying means for carrying said guidably-` supporting means in an endwise-looping path'of move-` ment between said forward and backward lines of move-l ment at opposite ends of said treatment line. p

10. An electro treating system for treating a continuous length of a exible or stretchable work material which comprises, a treating line made up of a group of longitudinally-aligned treating stations, means for engaging and driving successive portions of the work material length between entry and delivery ends of the line to thereby progressively advance the work material length there-` along, means for progressively subjecting the work material length lto electro treatment along the line, said firstmentioned means including means for guidably-supporting the work material along the line between the entry and delivery ends thereof, said first-mentioned means having work material engaging means cooperating with said guidable-supporting means to coordinate the movement of the work material between =the entry and delivery ends of the line to maintain a tension-free movement of the work material along the treatment line, and wherein: said means guidably-supporting the work material length along the treatment line has a plurality of spaced-apart transversely-open hangers, each of said hangers has a transverse arm on which the work material rests during its movement along said treatment line, means projects upwardly from said arms for maintaining the work material length in a guided aligned relation thereon, and means is operatively-positioned at the entry and delivery ends of `said treatment line for swinging said hanger arms transversely into and out of alignment with the work material length.

References Cited by the Examiner UNITED STATES PATENTS 2/ 1929 Gillis 204--208 7/ 1936 Krowsbein. 3/ 1956 Rayburn 204-206 9/ 1958 Swanton 204-28 11/ 1959 Cohn 204-206 9/ 1960 Villette 204-297 10/ 1962 Spurck 204-297 6/ 1963 Stone 204--28 FOREIGN PATENTS 10/ 1939 France.

1/ 1939 Great Britain.

JOHN H. MACK, Primary Examiner.

HOWARD S. WILLIAMS, R. L. GOOCH,

T. TUFARIELLO, Assistant Examiners. 

1. IN A SYSTEM FOR ELECTRO TREATING A WORK MATERIAL OF INDEFINITE LENGTH AND IN THE NATURE OF A FLEXIBLE OR STRETCH ABLE MATERIAL, A SERIES OF TREATMENT STATIONS DEFINING A TREATMENT LINE FOR TREATING THE MATERIAL, A DRIVEN ROLL AT AN ENTRY END OF SAID TREATMENT LINE AND A DRIVEN ROLL AT A DELIVERY END THEREOF ENGAGING SUCCESSIVE PORTIONS OF THE WORK MATERIAL TO ADVANCE IT ALONG SAID TREATMENT LINE, SAID DRIVEN ROLLS HAVING MEANS EFFECTING AN IMPOSITIVE ENGAGEMENT WITH THE WORK MATERIAL AND THE SPEED OF SAID ROLLS BEING COORDINATED TO ADVANCE THE WORK MATERIAL ALONG SAID LINE IN A SUBSTANTIALLY TENSION-FREE CONDITION, A CONVEYOR OPERATIVELY POSITIONED ALONG SAID LINE, A PLURALITY OF OPEN-END HANGERS CARRIED IN A LONGITUDINALLYSPACED RELATION ON SAID CONVEYOR TO PICK-UP SUCCESSIVE PORTIONS OF THE WORK MATERIAL AT THE ENTRY END OF SAID LINE AND GUIDABLY-SUPPORT AND MOVE WITH SUCH SUCCESIVE PORTIONS DURING THE ADVANCE OF THE WORK MATERIAL ALONG SAID LINE, AND MEANS PROGRESSIVELY DISENGAGING SAID HANGERS THROUGH THEIR OPEN ENDS FROM THE SUCCESSIVE PORTIONS OF THE WORK MATERIAL ADJACENT THE DELIVERY END OF SAID LINE AND BEING AGAIN RETURNED BY SAID CONVEYOR TO THE ENTRY END OF SAID LINE. 